Apparatus for pneumatically stopping spindle assemblies of a textile yarn processing machine in a predetermined position

ABSTRACT

An apparatus for automatically stopping rotation of a spindle assembly of a textile yarn processing machine in a predetermined position and which includes provision for facilitating the threading of a yarn end through the hollow axle of the spindle assembly. The apparatus comprises brake means including a brake shoe mounted on a reciprocating piston and a braking surface on the whorl of the spindle for initially stopping rotation of the spindle, pneumatic control means for directing pressurized air between the brake shoe and braking surface to thereby at least partially release the brake means and permit the spindle to slowly rotate after it has been initially stopped, and means including an aperture in the braking surface of the spindle whorl for carrying away the air directed between the brake shoe and brake surface to thereby re-establish the brake means to stop the spindle in a predetermined position wherein the aperture is aligned with the brake shoe. Concurrently, the air entering the aperture in the braking surface is directed outwardly through an outwardly directed channel in the spindle disc and which communicates with the hollow axle to thereby draw air through the hollow axle and thus facilitate the threading of the yarn end therethrough. The above braking and pneumatic control means may be positioned at each spindle of the machine, or they may be mounted on a movable carriage which may be brought to a spindle requiring servicing.

United States Patent Franzen APPARATUS FOR PNEUMATICALLY STOPPING SPINDLE ASSEMBLIES OF A TEXTILE YARN PROCESSING MACHINE IN A PREDETERMINED POSITION [75] Inventor: Gustav Franzen, Krefeld, Germany [73] Assignee: Palitex Project-Company GmbI-I,

Krefeld, Germany 22 Filed: Nov.29, 1972 21 Appl. No.: 310,567

[30] Foreign Application Priority Data Nov. 29, 1971 Germany 2159075 [52] US. Cl. 57/34 R, 57/58.49, 57/58.7, 57/58.83, 57/81, 57/88, 57/106 [51] Int. Cl D01h 1/24, DOlh 7/86, DOlh H10 [58] Field of Search 57/34.5, 34 R, 58.49, 58.7, 57/58.83, 58.84, 58.86, 88, 106, 78, 80, 81

[451 Apr. 23, 1974 Primary Examiner-John Petrakes [57] ABSTRACT An apparatus for automatically stopping rotation of a spindle assembly of a textile yarn processing machine in a predetermined position and which includes provision for facilitating the threading of a yarn end through the hollow axle of the spindle assembly. The apparatus comprises brake means including a brake shoe mounted on a reciprocating piston and a braking surface on the whorl of the spindle for initially stopping rotation of the spindle, pneumatic control means for directing pressurized air between the brake shoe and braking surface to thereby at least partially release the brake means and permit the spindle to slowly rotate after it has been initially stopped, and means including an aperture in the braking surface of the spindle whorl for carrying away the air directed between the brake shoe and brake surface to thereby reestablish the brake means to stop the spindle in a predetermined position wherein the aperture is aligned with the brake shoe. Concurrently, the air entering the aperture in the braking surface is directed outwardly through an outwardly directed channel in the spindle disc and which communicates with the hollow axle to thereby draw air through the hollow axle and thus facilitate the threading of the yarn end therethrough. The above braking and pneumatic control means may be positioned at each spindle of the machine, or they may be mounted on a movable carriage which may be brought to a spindle requiring servicing.

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MTENTEDAPR 23 I974 3805504 SHEET '11 0F 11 IIIIIIIIIIIIIA r I a I I I 0 APPARATUS FOR PNEUMATICALLY STOPPING SPINDLE ASSEMBLIES OF A TEXTILE YARN PROCESSING MACHINE IN A PREDETERMINED POSITION The present invention relates to an apparatus for braking and stopping the rotation of a spindle assembly of a textile yarn processing machine, such as a twister, spinning frame or the like, in a predetermined position.

In textile yarn processing machines, such as two-forone-twisters, it is often desirable to stop rotation of the spindle assembly in a given position, e.g., the position wherein the yarn emerging from the rotating portions of the spindle assembly faces the outside for access by the operator, upon the occurrence of yarn breakage or the formation of a full yarn package.

An apparatus of the above type is described in copending application, Ser. No. 264,816, filed June 21, 1972, and of common assignee. In the referenced prior application, a two-for-one twister is disclosed wherein the spindles are rotated by a drive belt and are adapted to be brought to rest in a predetermined position, namely, in a position in which the yarn passage channel opens outwardly on the surface side. Thereafter, the

operator can pull the yarn that is to be drawn off from the feed package without difficulty, for example with a threading needle in the event of an exchange of the feed package or in the event of a thread breakage. In accordance with the prior application, the stopping of the spindle is completed in two operations. First, the spindle is braked by a conventional spindle brake, and concurrently the tension roller associated with the spindle whorl is withdrawn from the guide belt, such that the driving force of the belt acting on the whorl is greatly reduced. When the spindle is initially braked in this way, the spindle will come to rest in a random position. The brake is next released temporarily, and the drive belt causes the spindle to start up once more with only a slight driving force. The spindle can be brought to a stop in a predetermined position with only a slight force, for example magnetically or by a mechanically acting grip device (see German Patent No. 1,269,549 and U.S. Pat. No. 3,269,103). Since during this intermediate restarting of the spindle, only a small driving force acts on the spindle, the spindle may be quickly stopped in the desired predetermined position, for example, wherein the yarn passage channel opens outwardly toward the operator.

German Patent No. 1,289,470 discloses the concept of pneumatically threading a yarn through the hollow axle of a spindle, and wherein an air passage opens into the yarn channel of the thread feeder disc and forms an injector with the yarn channel. The air passage communicates with a compressed air line, and when compressed air is blown in, a suction is developed in the hollow spindle axle through which the yarn is drawn from the feed package. More particularly, the yarn is passed over the upper end of the hollow spindle and directed downwardly therethrough where it is hurled outwardly by the compressed air passing through the yarn passage channel of the yarn feeder disc. The yarn is then guided upwardly so that its end can be attached to the take-up spool or can be. tied to the yarn of the takeup spool.

In accordance with the present invention, it is proposed to utilize a pneumatic control arrangement for actuating both a spindle brake and a yarn threading apparatus. Thus, it is an object of the present invention to provide a relatively simple device for braking and stopping a textile spindle in a predetermined position and wherein both the braking of the spindle and the stopping thereof in a predetermined position is effected pneumatically. It is a further object of the present invention to utilize the compressed air which is necessary for the braking function to also facilitate the yarn threading operation.

In accordance with the present invention, there is provided an apparatus which comprises a brake shoe which can be delivered pneumatically against a braking surface on a spindle whorl and which can be withdrawn in the opposite direction. Also, a compressed air outlet opens out through the braking surface of the brake shoe and is adapted to communicate with an inlet aperture which opens out in the braking surface of the spindle and which in turn communicates with the outwardly directed channel in the disc of the spindle to thereby form an injector.

By the above arrangement, the spindle initially decelerates and stops by means of the brake shoe which is delivered pneumatically against the braking surface on the whorl. Concurrently, the tension roller associated with the spindle is withdrawn from the drive belt so that the entrainment force thereof acting on the spindle is greatly reduced. Afterwards, pressurized air is directed through the outlet which opens out through the brake shoe to form an air cushion between the braking surface of the spindle and the braking surface of the brake shoe. This results in the adhesion between the braking surfaces being substantially reduced, and the spindle starts up again through the weak entrainment force of the drive belt. However, at that moment at which the outlet of a compressed air channel in the braking surface of the brake shoe and the inlet aperture in the braking surface of the spindle whorl are directly opposite each other, the air cushion between the braking surfaces breaks down since the pressurized air can enter directly from the brake shoe into the inlet aperture of the spindle. Thus, the braking surface of the brake shoe again comes to rest on the braking surface of the spindle, and the spindle is stopped in this position. The pressurized air, which emerges from the braking surface of the brake shoe flows into the inlet aperture of the spindle, and through the outwardly directed yarn channel in the disc of the spindle. An air passageway extends between the inlet aperture on the spindle whorl and the outwardly directed yarn channel, and the meeting of the air passageway and yarn channel is designed in an injector-like manner, thus the pressurized air causes a suction in the hollow spindle axle so tha a yarn end which is brought adjacent the upper end of the hollow spindle axle will be drawn through the hollow spindle axle and, under the effect of the pressurized air, will be conducted radially outwardly through the yarn channel. Thus, in accordance with the present invention, one source of energy, namely, compressed air, serves to actuate the brake shoe to initially stop the spindle, to permit adjustment of the stopping position until the predetermined location is reached, and then to thread the yarn through the hollow axle of the spindle.

The brake shoe of the present invention is operatively carried by a piston which is slidably mounted in a cylindrical housing. A valve controlled compressed air line opens into the housing on one side of the piston such that the brake shoe may be delivered against the braking surface of the spindle pneumatically. The pneumatic force acts against a spring force which is supplied by the restoring spring carried in the housing and contacting the other side of the piston. Thus, the pneumatic control for the brake shoe is of a very simple design and the use thereof costs little more than the customary purely mechanically acting brakes.

As will become apparent, it is immaterial to the present invention whether the braking surface of the spindle is positioned on an outer generated surface of the spindle or on the whorl of the same, or on a surface extending approximately perpendicularly to the spindle axis. Thus, the direction of movement of the brake shoe can be adjusted radially to the spindle, or it could be positioned parallel to the axis thereof.

In the illustrated embodiment of the present invention, the brake shoe is delivered radially against a cylindrical braking surface which is positioned on the whorl, and an inlet aperture opens radially therethrough. This configuration facilitates the automation of the individual operations of the apparatus and which will be further described hereinafter.

In accordance with a further feature of the invention, the brake shoe may be operatively connected to the tension roller for concurrent withdrawing and delivering movement. Thus, as the brake shoe is delivered to the braking surface of the spindle, the tension roller is withdrawn to thereby greatly reduce the entrainment of the drive belt, and when the brake shoe is withdrawn, full entrainment force is reestablished.

In accordance with a further feature of the invention, a fixed cylindrical housing having a piston and brake shoe can be associated with each spindle so that each spindle has a breaking device of its own as well as means for carrying out the threading procedure. In this connection, the deceleration procedure can be triggered by a thread detector of conventional design and which is associated with each spindle. Thus, each individual spindle may be stopped if the yarn brakes or the feed package is empty.

In accordance with another embodiment of the present invention, it is contemplated that the cylindrical housing with the piston and brake shoe may be mounted on a carriage which is transportable along the machine and which can be selectively brought up to the spindle that is to be serviced. In this case, the need for the above described braking apparatus on each individual spindle is eliminated, and this equipment may be brought up to that spindle position which requires a threading procedure or some other maintenance service by the operator.

Where the invention is mounted on a carriage, means are provided for bringing the carriage to a stop as it is conveyed along the machine and for automatically activating the same. In particular, a thread detector is associated with each spindle, and upon yarn breakage, the thread detector acts through a ratchet lever to cause a lever arm to swing into the working region of a rocking lever carried by the carriage. The actuation of the rocking lever actuates a compressed-air control valve and thereby triggers the pneumatic stopping and threading procedure, along with stoppage of the carriage. By this arrangement, the carriage, which may be conveyed along the machine by hand or motor, automatically comes to a stop and becomes active at that spindle which the thread detector has been caused to respond.

The conveying of the carriage may be effected by a motor hinged in suspended manner on the carriage such that a friction wheel driven by the motor engages a runner rail. Also, the wheel and motor may be pivoted away from the rail to terminate the movement of the carriage, such pivoting movement being controlled by an additional air actuated piston-cylinder unit. The conveyance of the carriage is thus effected by a motor acting through a friction wheel drive and the conveying or stopping movement thereof is triggered pneumatically so that once more a common source of energy may be used.

As a further aspect of the present invention, there may be provided a brake slide for each spindle whorl and positioned on the side thereof opposite the service side. The brake slide includes a brake shoe which is adapted to be delivered radially under a spring force against the whorl immediately when the thread detector responds to thereby stop the spindle prior to the arrival of the carriage. The brake slide is operatively controlled by a lever arm which also moves the tension roller away from the drive belt to thereby reduce the driving force during the braking action.

The above brake slide device makes allowance for the fact that in the event of a yarn breakage or the emptying of the feed package of a spindle, an immediate stopping of the spindle is desirable, i.e., before the carriage with the device for stopping the spindle in a predetermined position is brought up to the spindle in question. The continued rotation of the spindle could lead to obvious problems, for example the further withdrawal of the yarn from the feed package after breakage of the yarn can lead to loop formations and similar difficulties which complicate the joining of the broken yarns. Thus, in accordance with the present invention, a brake slide is associated with each spindle and which can be delivered radially under spring force against the whorl by a lever arm. The lever arm also causes the tension roller to draw off from the drive belt to thereby greatly reduce the entrainment force of the drive belt, so that the spindle comes to a stop immediately after response of the thread detector, albeit in a random rotational position. Furthermore, the movement of the brake slide displaces a control body into the path of motion of the switch lever which is carried on the carriage. The switch lever in turn actuates the compressed air control valve and causes a stopping of the arriving carriage. The holding of the spindle and threading of the yarn is then undertaken by the apparatus in accordance with the invention which is mounted on the carriage and the preliminary brake which is first caused to respond and which is fixedly mounted at the rear side of each spindle is released.

When the threading of the yarn is completed, the rotation of the spindle is again started by actuation of a manual switch which acts through a piston-cylinder unit in such a way that the latter resets the brake slide and delivers the tension roller once more against the tangential drive belt. Thus the tension roller, which was moved away from the whorl at the time when the brake slide was operatively moved against the whorl so that the belt contacted the whorl with only slight entrainment force, is brought back again into that position in which the entainment force of the belt is fully effective on the whorl.

As mentioned, all of the deceleration and stopping procedures as well as the threading-through procedure for the yarn are accomplished pneumatically, i.e., by means of a single source of energy. The actuation of the apparatus can be brought about by'hand or automatically, but the automatic triggering by means of thread detectors is particularly advantageous. Where the apparatus of the present invention is associated with each individual spindle, the thread detector acts directly on the associated apparatus and causes this to respond. In the event of a conveyable apparatus, it is advantageous to associate with each individual spindle an additional brake, which is initially caused to respond by the thread detector and the function of which is later taken over by the apparatus of the present invention which is brought up on the carriage. In this case, the apparatus undertakes the threading through procedure for the yarn and also brings about the resetting of the stationary brake into its initial non-operative position. Further, the apparatus controls the tension roller so that the spindle may be restarted after conclusion of the work to be carried out at the spindle. The apparatus of the present invention can be used either in the case where a withdrawal of the tension roller from the drive beltis employed to facilitate the deceleration of the spindle and as described above, or in a case where the spindle is removed from the belt in order to greatly reduce the entrainment force of the belt. In the event of the removal of the spindle from the belt, it is merely necessary to adapt the present apparatus in its arrangement to the swung-out position of the spindle. Thus, in the event of the stationary arrangement of the apparatus at each spindle, it would'be necessary to mount the same at an angle corresponding to the movement of the spindle, and where a carriage is employed, to arrange the apparatus on the carriage with a corresponding inclination.

As will be apparent from the above, it is a further advantage of the present invention that a single energy source, namely compressed air, effects not only the deceleration procedure and the stopping of the spindle in a predetermined position,but also the threading of the yarn end, and without any special grip devices of a mechanical or electrical type being required.

Other objects and advantages of the present invention will appear as the description proceeds, when taken in connection with the accompanying drawings, in which:

FIG.'1 is a sectional side elevational view of doubletwist spindle assembly, and embodying the features of the present invention;

FIG. 2 is a front elevational view, partly sectioned, of the apparatus shown in FIG. 1, and viewed from the service side FIG. 3 is a fragmentary front view of the braking surface of the brake shoe of the present invention;

FIG. 4 is a sectional'top plan view takensubstantially along the line 4-4 in FIG. 2, and illustrating the spindle braking device;

FIG. 5 is a fragmentary top plan view similar to FIG. 4, partly broken away, and showing the rocking lever for'mounting the tension roller;

F IG. 6 is a sectional side elevational view of another embodiment of the present invention and wherein the brake means and pneumatic controls are conveyable along the apparatus;

FIG. 7 is a fragmentary view of the lever arm looking in the direction of the arrow 7 of FIG. 6;

FIG. 8 is a front elevational view, partly sectioned, of the apparatus shown in FIG. 6, and viewed from the service side;

FIG. 9 is a sectional top plan view taken substantially along the line 99 of FIG. 8;

FIG. 10 is a sectional side elevational view of still another embodiment of the present invention and wherein the brake means and pneumatic controls are conveyed along the apparatus by automatic means;

FIG. 11 is a front elevational view, partly sectioned of the apparatus shown in FIG. 10, and viewed from the service side;

FIG. 12 is a sectional top plan view taken substantially along the line 12-12 of FIG. 11; and illustrating the preliminary braking device in operative position;

FIG. 13 is a view similar to FIG. 12, the brake means and pneumatic controls on the carriage being shown in operational position and the preliminary braking device being withdrawn;

FIG. 14 is a fragmentary sectional view taken substantially along the line 14-14 of FIG. 13;

FIG. 15 is a fragmentary sectional view taken substantially along the line 15-15 of FIG. 12;

FIG. 16 is a view similar to FIG. 14 but showing the lever arm withdrawn to its normal operating position; and

FIG. 17 is a fragmentary sectional view taken substantially along the line 17-17 of FIG. 12.

Referring more specifically to the embodiment of the present invention shown in FIGS. 1 to 5, there is illustrated a pneumatic device for the deceleration and stopping of a spindle, as well as for the threading of the yarn and through the hollow spindle axle. The device is fixedly mounted on the service side of the textile processing machine in front of each spindle.

The spindle beam is designated generally in all of the figures by the numeral 1, and the beam mounts the I bearing stock 2 of each spindle.

The spindle rotor 3 of each spindle is mounted so as to be freely rotatable on the bearing stock 2, and includes a whorl 4 which is operatively contacted by the tangential drive belt 5, which drives all the spindles. The belt 5 is pressed against the whorl 4 by means of the tension roller 6-. In this regard, as FIGS. 4 and 5 show, the tension roller 6 is mounted so as to be rotatable on the rocking lever 7, which is pivoted on the bearing block8, the block 8 in turn being fixed to the spindle beam 1. A drawspring 9 acts on the rocking lever 7 of the tension roller 6 in the direction of the spindle beam 1, the spring 9 being fastened at one end to the rocking lever 7 at the point 10 and at its ohter end to the spindle beam 1 by means of the adjustment screw 11'. The path of swing of rocking lever 7' toward the tangential drive belt 5 is limited by the adjustable stop screw 12, which is carried on the rocking lever 7 and which, in the operational position shown in FIG. 5, butts against the spindle beam 1 to thereby limit the movement of the rocking lever 7.

As the drawings further reveal, the spindle rotor 3 carries the spool support 13 for the reception of the feed package 14 in the conventional manner, and the support 13 includes the protective pot 15. The spool 13 is freely rotatable about the spindle rotor 3 in the customary manner, and is prevented from co-rotation by magnets 16 which are found in the separators 17 on both sides of each spindle, and which are fastened by means of supporting columns 18 to the spindle beam. Extending upwardly beyond the protective pot 15 and forming a part of the spool support is the hollow spindle axle 19, through which the yarn 20, which is drawn off from the feed package 14 is axially pulled. The lower end of the hollow axle 29 communicates with an outwardly directed channel 21 in the yarn feeder disc 22 which forms a part of the spindle rotor 3. The yarn to be twisted emerges from the channel 21 and swings in its path to the take-up device (not shown) in a balloonshaped manner around the protective pot 15 and within the separators 17 and the cup-shaped balloon limitor 23. As will be apparent from the drawings, the protective pot 15 is provided in the lower region with two large opposed openings 24, between which the webs 25 are situated.

The above described basic construction is present in the case of all the spindles shown. A different spindle construction can, of course, be chosen, since the spindle construction as such does not form part of the invention.

The operation of the apparatus according to the present invention for the deceleration and stopping of the spindle rotor 3 and for the automatic threading of the yarn through the spindle hollow axle l9 and channel 21 of the thread storage disc 22, and further upwardly toward the take-up device will now be described.

As a result of a signal which is given by, for example, a thread detector, the tension roller 6 is drawn away from the whorl 4, or the tangential drive belt 5, to such an extent that the tangential drive belt contacts the whorl 4 only lightly and with only slight entrainment force. Concurrently, a brake shoe 36 moves from the service side toward the annular braking surface 26 of the whorl 4 and stops the whorl 4 and thus the spindle rotor 3. Subsequently, the brake shoe 36 is at least partially released and then again fully applied when the spindle rotates to a predetermined position, namely, the position wherein the radial bore 27, which is situated in the whorl 4 finds itself in a forwardly directed position, note FIGS. 1 and 4. The bore 27 communicates with an axial passageway 28 which extends axially through the whorl 4 and opens out into the channel 21 of the yarn feeder disc 22. Thus, when compressed air is blown into the bore 27, the air flows upwardly through the passageway 28 and, in accordance with FIG. 2, further through the outwardly directed channel 21. This produces a partial vacuum or suction in the hollow spindle axle 19 via the yarn passage channel 29 which opens out into the channel 21 so that a yarn which is held over the entry end 30 of the hollow spindle axle 19 is drawn downwardly through the axle 19 and is grasped in the channel 21 by the compressed air and is hurled radially outwardly. Opposite the point at which the channel 21 opens out radially, the balloon-limiter 23 is provided with the downwardly projecting air and thread guide surface 31. The surface 31 upwardly deflects the compressed air emerging from the channel 21 so that the entrained yarn is also deflected upwardly and takes the path designated by the arrow 32. Thus the yarn can be grasped above the spindle and can be connected to the take-up package. If the threading-through of the yarn is effected by reason of a thread breakage, then the joining-up is efiected with the free yarn end on the take-up spool. This depicted pneumatic threading procedure is effected in accordance with the present invention directly in conjunction with the deceleration and stopping of the spindle. The brake means for decelerating and stopping the spindle is indicated generally at 33, and means 33 being fixed to the spindle beam 1 and in association with each individual spindle. The means 33 comprises the cylindrical housing 34, through which the piston 35 extends longitudinally. The front end of the piston 35 includes an arcuate brake shoe 36, note FIG. 3. A helical spring 37 encompasses the piston 35 in the interior of the housing 34, the spring 37 abutting the inner frontal surface of the housing at one end and the ring flange 38 of the piston 35 at the other end, the flange 38 being fixed to the piston 35. The compressed air line 41 opens out into the space 40 behind the ring flange 38, and the second compressed air line 42 is fastened to the rearward free end of the piston 35 and communicates with the channel 43 which opens outs into the braking surface 44 (FIG. 3) of the brake shoe 36. The channel 43 has a central outlet 45 (FIG. 3), which is adapted to lie exactly opposite the bore 27 in the whorl 4, as well as two transverse slots 46 communicating with the outlet 45 in the manner shown in FIGS. 1 and 3.

In operation, the means 33 is triggered by, for example, a thread detector or the like, pressurized air initially flows through the comrpessed air line 41 into the space to displace the piston 35 in the direction of the braking surface 26 of the whorl 4. When the shoe 36 comes in contact with the surface 26, the rotation of the rotor 3 stops. Concurrently, and as described in more detail hereinafter, the withdrawal of the tension roller 6 from the whorl 4 is effected so that the entrained force of the tangential drive belt 5 is greatly reduced and only a weak entrainment of the whorl is effected, to thereby facilitate the braking action.

It will be understood that the above braking operation will stop the spindle in a random orientation, and in order to orientate the spidnle in a desired predetermined position and to thread-through of the yarn, pressurized air is sent through the line 42 and through the channel 43 of the piston 35. This may be effected by an automatic delay valve or by hand. The pressurized air exits through the outlet 45 and slits 46 and, assisted by the force of the spring 37, draws the brake shoe 36 slightly away from the whorl 4. In other words, the compressed air seeks to emerge between brake shoe 36 and surface 26, and an air cushion develops between whorl 4 and brake shoe 36. There remains however a slight entrainment force resulting from the tangential drive belt 5 contacting the whorl 4 which acts to further rotate the spindle. The rotation of the whorl 4 will be less than 360 and ends at that moment at which the bore 27 of the braking surface 26 and the outlet 45 of the channel 43 in the piston 35 lie opposite one another. At this position, the compressed air can flow out of the channel 43 directly into the bore 27, and further through the passageway 28 to carry out the above described threading-through procedure of the yarn. When the bore 27 and the channel 43 lie opposite one another, the air cushion previously present between the brake shoe 36 and the braking surface 26 dissipates, and the piston is pushed forwardly again by the compressed air in the space 40 such that brake shoe 36 frictionally engages the braking surface 26 of the whorl 4. A direct connection between the channel 43 and the bore 27 is thus established. When it is desired to restart the spindle, the pressure in lines 41 and 42 is released and the piston 35 is withdrawn under the force of the spring 37. Thus the frictional contact between brake shoe 36 and whorl 4 is released, and the spindle can run on again, it being understood that the tension roller 6 is concurrently swung toward the whorl 4 as hereinafter described.

FIGS. 4 and illustrate the cooperation of the brake means 33 with the tension roller 6. As best seen in FIG. 4, the guidebars 48 are pivgtally connected to brake shoe 36 at 47 and the other ends of the bars are fastened to the yoke 49. The bars 48 are positioned above the spindle beam on opposite sides of the whorl 4 and the yoke 49 has a slotted hole 50 which receives the pin 51 connected at the free end of the rocking lever 7. Thus when the piston 35 now moves in the directin of the arrow 52 as seen in FIG. 4, the lever 7 swings counterclockwise as seen in FIGS. 4 and 5 from the position shown in solid lines in FIG. 5 to the position shown in dot-dash manner. Also, the stop screw 12 is drawn away from the spindle beam 1. By this arrangement, the tangential drive belt 5 is withdrawn, and the entrainment force acting on the whorl 4 is reduced to a relatively insignificant magnitude.

The resetting of the tension roller 6 is effected by the reverse movement of the piston 35 acting through the guide bars 48. When this occurs, the driving frictional connection between the tangential drive belt 5 and whorl 4 is re-established to rotate the spindle.

As seen in FIGS. 1-3, suitable valves and electrical switches are provided to actuate the brake means 33. More particularly, the brake means 33 may for example be designed to be activated electrically in the event of a yarn breakage. In such case, the thread detector is positioned in the path of the yarn from the feed package 14 to the take-up package. An electrical line 54 from the thread detector actuates the solenoid valve 53 through which the supply of compressed air is controlled. In the illustrated embodiment, two compressed air lines are provided having different pressure levels, namely the compressed air line 55 (FIG. 1) for the actuation of the brake, and the compressed air line 56 for thebuild-up of the air cushion between the brake shoe 36 and the whorl 4 and for the threadingthrough of the yarn. By design, the pressure in the lines 55 and 56 are coordinated to the size of the individual pressure surfaces upon which they act. Thus the specific pressure force applied in the space 40 is a function of the size of the annular surface of the ring flange 38. In addition, the compressed air which flows through the channel 43 of the piston 35 must be sufficient for both the threading procedure and the build up of an air cushion between brake shoe 36 and braking surface 26 of the whorl 4, and yet it must not be so great as to prevent the resetting of the piston 35 when the predetermined position is reached.

Of course, it would be possible to charge both lines, 41 and 42, with compressed air of equal pressure, which presupposes, however, a corresponding coordination of the effective surfaces on the ring flange 38 and the braking surface 44 of the brake shoe 36, the surface sizes of which would undoubtedly be different from those illustrated. In addition, the different pressure magnitudes could be adjusted by the incorporation of suitable throttles (not shown).

In accordance with the above described embodiment of the present invention, the deceleration and stopping of the spindle is actuated by a thread detector. It will be understood however that a hand operated pushbutton 57 could be employed, the actuation of the push-button 57 causing the actuation of the solenoid valve 53. Q

A further hand operated push-button 58 releases the compressed air into the line 42 and allows it to flow into the channel 43 of the piston 35. Thus, for example,

in the event of a yarn breakage the spindle may be stopped automatically by the shifting of the piston 35 while the tension roller 6 is concurrently withdrawn. Further operation of the apparatus occurs only when the operator reaches the spindle in question and actuates hand push-button 58.v Its actuation is effected against a spring force so that the flow of compressed air into the channel 43 is interrupted immediately upon the release of the button 58 after termination of the threading-end procedure.

In the above described embodiment, a brake means 33 is fixedly mounted at each spindle assembly. In accordance with another embodiment as shown in FIGS. 6 to 9, the means for decelerating, adjusting and stopping the spindle, as well as for the threading through of the yarn, is associated with several spindles and travels up to that spindle assembly which is occupied by an empty feed package or at which a yarn breakage has occurred. In the case of the following description, the mode of operation of the apparatus in the event of a yarn breakage is discussed. Also, those parts which have already been described in conjunction with the embodiment illustratedin FIGS. 1 to 5 are provided with the same reference numbers and are discussed hereinafter only briefly, it being understood that their construction and mode of operation are similar to those of the above described embodiment.

As FIGS. 6 and 8 make clear, the brake means 33 is carried by a carriage, which is supported by two rollers 60 on the angle rail 61, the rail 61 being a part of the machine frame and extending along one side of the machine. Furthermore, the carriage is supported on the perpendicular leg of the angle rail '62 which is fastened below the spindle beam 1 by means of the horizontally disposed rollers 63 and 64, the rollers 63 and 64 being mounted in the bearing blocks 65 and 66, which in turn are fixed to the mounting plate 67 of the carriage. The cylindrical housing 34 of the brake means 33 is fastened to the upper edge of the mounting plate 67, the construction of which corresponds to that of the above described embodiment. The two rollers 60 are mounted at the lower edge of the mounting plate 67, and two fixed brackets 68 depend downwardly thereform. A pivot pin 69 is pivotally mounted between the brackets and carries a two-armed rocking lever 70 which grips under the angle .rail 61 with the end 71 having the brake lining 72. An actution bar 74 with the handle is situated on the other arm 73 of the lever 70. If the carriage is shifted by hand along the machine on the angle rail 61, and along the angle rail 62, it may be stopped by swinging the actuation bar 74 from the position shown in dot-dash lines to the position shown in solid lines. Thus, through the swinging of the two-armed lever 70, the brake lining 72 thereof is made to come into frictional contact with the angle rail 61 to thereby slow down and stop the carriage.

A bracket 76 is fastened to the angle rail 61 as seen in FIG. 6, and a roller 77 is mounted on the bracket 76. The roller 77 serves for the support of a compressed air tube 78, through which the compressed air may be supplied to the apparatus. Such rollers 77 are distributed over the entire length of the machine. The

air tube 78 opens out into the pipe 79, which forms a part of the illustrated carriage.

In accordance with the present invention, the carriage as shown in FIGS. 6 to 9, may be stopped exactly at that spindle assembly at which a yarn breakage has occurred, and in addition, the whorl 4 is stopped at a predetermined location wherein the bore 27 of the whorl 4 is in alignment with the outlet 45 of the channel 43. In this regard, it is assumed that, upon a yarn breakage, a thread detector (shown schematically in FIG. 6) gives an electrical impulse causing the electromagnet 80 having a sliding armature 81 to respond, so that the armature 81 is drawn-in into the magnet coil of the electromagnet 80. This allows the ratchet lever 82, which is pivoted at 83 on the machine frame, to swing toward the left as shown in FIG. 6. Thus the pawl 84, which was supported on the ratchet lever 82, is released and swings downwardly. The pawl 84 is pivoted at 85 on the machine frame, and includes the downwardly directed lever arm 86. The lever arm 86 swings with the downward swinging of the pawl 84 out of the position shown in solid lines to the position shown in dot-dash lines. The lever arm 86 has the shape shown in FIG. 7, which is similar to a ships anchor. In particular, the lower end of the lever arm 86 includes two lateral arms 87 having a V-shaped lower edge having symmetrically inclined lower surfaces 91 to form an obtuse angle. As mentioned, in the event of a thread breakage, the lever arm 86 assoicated with the individual spindle in question is pivoted on the machine frame and attains the vertical position which is shown with dot-dash lines in FIG. 6. If the carriage is now conveyed along the machine, one of the inclined surfaces 91 of the lever 86 comes into contact with the two armed rocking lever 89 which is pivotally connected to the carriage at 88. More particularly, the engagement of the short lever arm 90 of the rocking lever 89 with the inclined surface 91 causes the lever arm 90 to move downwardly to the position shown in dot-dash lines, and the lever arm 92 of the rocking lever 89 to correspondingly swing upwardly, as indicated likewise in FIG. 6. Through the swinging of the lever arm 92, the valve tappet 93 is actuated, which allows the valve 94 to respond immediately. Compressed air, coming from the tube 78, thereby flows through the pipe 79, the throttle 95, the pipe 96, and to the pressure reducer 97,-having a pressure gauge 97. At this point, a pressure reduction is effected and the air then flows with this lesser pressure through the pipe 98 via the pipe connection 99 to the valve 94 and then through the line 41 into the space 40 behind the ring flange 38 in the cylindrical housing 34. Behind the throttle 95, there branches off a pipe 100 which is under the higher pressure and which opens out into the delay valve 101. The valve 101 is initially in the closed position.

Since the actuation of the rocking lever 89 by the lever arm 86 has resulted in compressed air having lesser pressure to flow into the space 40 of the brake means 33, the piston 35 immediately advances and presses the brake shoe 36 against the braking surface 26 of the whorl 4, so that the whorl 4, and the spindle rotor 3, come immediately to a standstill. The electrical impulse of the thread detector thus brings the lever amr 86 into such a position that the rocking lever 89 of the carriage comes into contact with the arm 86 as the carriage is slowly advanced along the machine. Immediately upon this occurring, the brake shoe 36 is moved forwardly to halt the carriage. More particularly, the arcuate braking surface 44 of the brake shoe 36 comes into contact with the braking surface26 of the whorl 4, and a centering of the two brake surfaces with regard to one another is effected, in that upon the coming together of the two braking surfaces the carriage experiences a corresponding displacement in either the direction of travel or in the opposite direction, in such a way that the axis of the opening 45 in the piston 35 perpendicularly intersects the axis of rotation of the spindle.

A pipe 105 branches off from the space 40 and leads to the delay valve 101 via the connecting piece 104 and the valve 103. The valve 103 is normally open, however, it may if desired be closed by means of the lever 102. The air which flows into the delay valve 101 actuates the same after a suitable delay period which is adjustable by the adjusting screw 101'. After the delay, the valve 101 is open so that compressed air flows from the pipe 100 into the line 106, which corresponds to the line 42 of the previous embodiment. From the line 106, the compressed air flows into the channel 43 of the piston 35, so that a pressure cushion builds up between the surface 44 of the brake shoe 36 and the braking surface 26 of the whorl 4, which results in a slight withdrawal of the brake shoe 36 from the braking surface 26 so that the spindle rotor 3 is able to rotate slowly under the traction force of the tangential drive belt 5. When the bore 27 and the opening 45 of the channel 43 lie opposite to one another, the air coming out of the channel 43 flows freely into the bore 27 and emerges via the passageway 28 from the outlet channel 21 of the disc 22. Also, the pressure cushion between brake shoe 36 and braking surface 26 dissipates so that the brake shoe 36 comes into firm engagement with the braking surface 26 and therefore the whorl 4 again comes to a stop. The threading procedure is thereafter effected in the manner described above.

When the pneumatic threading procedure is completed and the operator has fixed the yarn breakage, the spindle is set in motion again by the operator shifting the bar 107 which is mounted on the carriage for movement transversely to the longitudinal direction of the machine. More particularly, the bar 107 as shown in solid lines in FIG. 6 is moved into the position shown in dot-dash lines by means of the pressure plate 108 which can be actuated for example by the knee. This displacement is effected against the force of the spring 109 in the housing body 110. The free end of the bar 107 strikes against the depending lever arm 86 and swings the latter out of the vertical position shown in dot-dash lines in FIG. 6 into the inclined position shown in solid lines so that the pawl 84 again finds itself in a position in which it can be supported on the ratchet lever 82, when the magnet armature 81 moves back out to the position shown in FIG. 6. This movement of the armature 81 is effected by the thread detector. More particularly, the effect of the repaired yarn again acting on the detector opens the circuit to the magnet coil of the electromagnet so that it becomes currentless and the magnet armature 81 becomes free and swings toward the ratchet lever 82 in the clockwise direction. Thus the pawl 84 is supported on the lever 82. If the operator then releases the button 108 and thus the actuator bar 107, the spring 109 will withdraw the bar into the position shown in solid lines so that the lever arm 86 can again swing into the vertical position upon a signal from the thread detector. It will also be understood that the above described movement of the bar 107 and lever arm 86 permits the rocking lever 89 to assume its solid line position such that valve 94 is closed, causing the piston 35 to withdraw.

As in the case of the preceeding embodiment shown in FIGS. 1 to 5, a withdrawal of the tension roller 6 from the whorl-4 occurs with the delivery of the brake shoe 36 against the braking surface 26 of the whorl 4. This is effected substantially in the same manner as has been described in connection with the FIGS. 4 and 5,

with the exception that the bars 48, which are con-.

fro along its working region and stops, as in the case of the preceeding illustrated embodiment, at that spindle assmebly where a threading procedure is to be carried out. Here again, the carriage comprises a mounting plate 67 and is supported by means of two rollers 60 on an angle rail 61 which extends along the machine and which has a double-angle profile as shown in FIG. 10. A motor driven friction wheel 1 11 contacts the rail 61 from below, the motor 112 including a gear 1l2"which is suspended eccentrically on the mounting plate 67 by means of two brackets 113 which are arranged on both sides of-the motor 112, note FIG. 11. Thus, the weight of the motor and gearpresses the friction wheel] 11 against the angle rail 61. Moreover, the carriage is guided with the mounting plate 67, as in the case of the preceding embodiment, by means of the further rollers 63 and 64 on the angle rail 62 which in turn is fastened to the spindle beam 1. Also, in the case of this embodiment, rollers 77 are positioned along the length of the machine for the guidance of the compressed air tube 78.

If the motor 112 and gear 112 are in the position shown in solid lines in FIG. 10, the friction wheel 111 contacts the angle rail 61, so'that the carriage runs continuously along on the machine. It is contemplated that the motor 112 runs continuously during the operation of the machine and is not switched off. The power supply of the motor is effected via the current connector 116 from the live rail 117 which is enclosed by the housing 118 and extends along the machine frame adjacent the angle rail 61. In order to stop the carriage at a desired point, the motor is swung into the position shown in dot-dash lines in FIG. 10, so that the friction wheel 1 1 1 is released from the angle rail 61. This swing can be carried out by hand, for which the actuation bar 114 with the handle 115 is mounted on the motor.

with the several spindles. The carriage travels to and The carriage of the embodiment of FIGS. 10-17 differs from the one in the embodiment of FIGS. 6 to 9 in that the deceleration and stopping of the spindle is not effected solely by the brake shoe 36 of the brake means 33. Here, there is associated with each spindle an additional fixed spindle brake. As will be apparent, the carriage needs a certain time to arrive at the spindle at which a yarn breakage has occurred. This can present a problem since the broken yarn continues to be withdrawn from the feed package, and unless a yarn catch device is present, the free yarn end can wind around the spindle rotor or parts of the same, making it difficult for the operator to free the windings and find the yarn ends to be joined. it is therefore desirable that the spindle come immediately to a standstill in the event of a yarn breakage, rather than continuing to rotate until the carriage has reached the spindle in question.

As seen in FIGS. 10 to 17, a stationary or fixed spindle brake isassociated with each spindle and lies on the side thereof opposite the brake shoe 36, namely on the same side as the tension roller 6. The fixed spindle brake is desinged to respond immediately when the thread detector associated with the spindle signals a yarn breakage. Before describing the details of the fixed spindle brake, it will be noted that the tension roller 6 is somewhat different from the prior embodiments. In particular, the tension roller 6 is mounted in the short leg of the lever arm (note FIG. 13) the arm 120 being pivotal about the pivot pin 119 which in turn is mounted on the bearing bracket 8 which is secured on the spindle beam 1.

The long leg of the lever arm 120 forms a pawl which cooperates with the ratchet 121, the lever 121 being pivotal about the stationary pin 122. If the lever 120 is in the position shown in dot-dash lines in FIG. 12 and 13, the arm 120 will be held in this position by the ratchet lever 121. Thus the tension roller 6 is pressed against tangential drive belt 5, such that the drive belt 5 drives the spindle rotor 3. The lever arm 120 assumes this position against the force of the spring 123, which extends between the stationary abutment 124 and the hinge point 125, and which lies around the bar 126 which-passes through the abutment 124, note FIG. 15. The lever arm 120 is connected with a brake slide 128 having an arcuate brake shoe 129 by means of a perpendicularly extending index pin 127. The brake slide 128 is guided for radial movement against the whorl 4 by the guides 130 which are fixed to the frame. The connection between slides 128 and index pin 127, and thus with the lever 120, is not however always effected, but rather such connection is only effected when the brake slide 128 is moved forwardly against the whorl 4, note FIG. 15. As shown in FIG. 14, the brake slide 128 and brake shoe 129 are withdrawn from the braking surface 26 of the whorl 4, in which case the index pin 127 is below and disconnected from the slide 128. In this latter position, the slide 128 is held in the withdrawn position by the spring 152 which extends between the stationary stop 131, which extends upwardly into the slot 132 in the slide 128, and the rearward end 133 of the slot 132. The index pin 127 is slidably mounted within the sleeve 134 which extends downwardly from the lever arm 120 and is fixedly connected thereto. A spring 135 is also positioned within the sleeve 134, the spring 135 being supported between a shoulder in the sleeve 134 and a ring collar 136 on the index pin 127. The spring 135 is fully extended as shown in FIGS. 15 and 16 when the free upper end of the index pin 127 projects into the slot 132 of the slide 128, and the spring 135 is compressed when the free end of the index pin 127 lies below the brake slide 128, note FIG. 14.

When the apparatus is operating normally, the index pin 127 is in a position shown in FIG. 16, and the lever arm 120 is in the position shown in dot-dash lines in FIGS. 12 and 13, the arm 120 being held in such position by the ratchet lever 121. The brake slide 128 is withdrawn from the whorl 4 as shown in FIGS. 13 and 16, and is held in such withdrawn position by the spring 152. Should the yarn break, the thread detector responds to actuate the electromagnet 137, which pulls in the armature 138 against the force of the spring 139. This movement causes the ratchet lever 121 to swing in a counterclockwise direction, so that the ratchet lever 121 releases the lever arm 120 so that the arm 120 swings in a clockwise direction about its pivot pin 119 and under the force of the spring 123. The sleeve 134 and index pin 127 move with the arm 120 and carry the brake slide 128 against the whorl 4 to the position shown in FIG. 15. Concurrently, the short leg of the lever arm 120 causes the tension roller 6 to be withdrawn from the drive belt, so that the tangential drive belt contacts the whorl 4 only with a slight force. The force does not rotate the whorl however since it is held fast by the brake shoe 129. Thus the spindle is immediately stopped and held against rotation while the carriage approaches.

As seen in FIGS. 10 and 15, the carriage includes a fixed arm 140 having a V-shaped bottom edge similar to the inclined surfaces 91 on the lever arm 86 as seen in FIG. 7. The lower end of the pin 127 mounts a mushroom-shaped body 141. Thus when the carriage approaches the spindle in question, the arm 140 engages the body 141 such that the body 141 and pin 127 are depressed against the force of the spring 135.

As seen in FIG. 10, the downward movement of the mushroom-shaped body 141 resulting from its engagement with the arm 140 causes the rocking lever 89 to rotate counterclockwise and thereby actuate the valve 94. The valve 94 not only triggers the functions described above in conjunction with the other embodiments, but also acts to swing the gear and motor 112 about the axis defined by the brackets 113. In this regard, a pneumatic unit 142 is fastened to the mounting plate 67 by means of the supporting arm 146, the piston 143 of the unit adapted to engage the arm 153 which is fixed to the gear 112 and extends upwardly as best seen in FIG. 10. This engagement causes the motor 112 and gear 112 to swing counterclockwise so that the friction wheel 111 is withdrawn from the runner rail 61. The pneumatic unit 142 is connected to the line 41 via the pipe 145 and thus acts concurrently with the displacement of the piston 35 against the whorl 4. Thus when the arm 140 engages the mushroom-shaped body 141, the brake slide 128 is released but the spindle is held fast by the concurrent application of brake shoe 36 of the piston 35. Upon the application of the brake shoe 36 against the whorl 4, the upper free end of the index pin 127 drops out of the slot 132 of the slide 128, and the slide 128 and the brake shoe 129 are withdrawn from the whorl by the force of the spring 152. In this regard, it should be noted that-the withdrawal of the slide 128 does not result in any movement of the lever arm 120. Thus the arm 120 remains in its forward position, and is shown in FIGS. 12 and 13 in solid lines. The braking function of the brake shoe 129 is thus replaced by the brake shoe 36 on the piston 35 of the brake means 33. The operator may now actuate the pneumatic control for orienting the spindle and actuating the threading procedure by causing compressed air to enter the channel 43 in the piston 35. As in the previous embodiments, this at least partially releases the braking force between the shoe 36 and braking surface 26 on the whorl 4 by developing an air cushion therebetween. When the bore 27 and the whorl 4 is aligned with the bore 43 in the piston 35, the air cushion is dissipated and rotation is stopped. The air entering the bore 27 passes through the passageway 28 and exits through the channel 21 to permit the threading through of the yarn, all as described above in connection with the prior embodiments. This automatic positioning of the spindle and threading procedure may if desired be triggered automatically by means of a delay valve 101 as described in conjunction with FIGS. 5 to 9.

Referring finally to FIG. 16, there is shown a mechanism for resetting the tension roller 6 against the drive belt 5 when the broken yarn has been repaired, this mechanism forming part of the system for also moving the carriage away from the spindle. In this regard, there is provided a switch lever 148, which is situated laterally of the cylindrical housing 34. Manual actuation of the lever 148 results in the opening of a valve and permits compressed air to enter piston-cylinder unit 149. A piston 154 is operatively controlled by the unit 149 and extends coaxially with the bar 156. The bar 156 is slidably mounted to the beam 1 by the strap 155 and is pivotally connected to the lever arm at 125, which is also where the bar 126 is connected. The piston 154 is adapted to push the bar 156, together with the lever arm 120, against the force of the spring 123 and until the lever arm 120 comes into contact with the ratchet lever 121 and is held thereby. Upon this movement, the index pin 127 is lifted into the slot 132 by the force of the spring 135 to arrive at the position shown in FIG. 16. This permits valve 94 to close, and the piston 143 is then withdrawn by its valve control so that the motor 112 and gear swing clockwise as seen in FIG. 10 and the friction wheel 111 comes into abutment against the angle rail 61. Thus the carriage moves on from the spindle. Once the mushroom-shaped body 141 is returned to its initial position as seen in FIG. 20, it remains outside the path of the arm as the carriage moves along the machine until the thread detector again causes the lever arm 120 to swing in the clockwise direction and thereby bring the mushroomshaped body 141 once again into the path of the arm 140 to stop the carriage.

In the drawings and specification, there have been set forth preferred embodiments of the invention, and although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation.

That which is claimed is:

1. A textile yarn processing apparatus such as a twister, spinning frame or the like and having a plurality of rotatable spindle assemblies for processing of yarn each of said spindle assemblies including a hollow axle and an outwardly directed channel communicating with said hollow axle and through which the yarn is adapted to travel, a whorl portion, and a tangential drive belt adapted to operatively engage said whorl 

1. A textile yarn processing apparatus such as a twister, spinning frame or the like and having a plurality of rotatable spindle assemblies for processing of yarn each of said spindle assemblies including a hollow axle and an outwardly directed channel communicating with said hollow axle and through which the yarn is adapted to travel, a whorl portion, and a tangential drive belt adapted to operatively engage said whorl portion to rotate said spindle assembly, the improvement therewith of means for stopping rotation of said spindle assembly in a predetermined position comprising brake means for initially stopping rotation of said spindle and control means for at least partially releasing said brake means to permit rotation of said spindle assembly only until said predetermined position is reached, and means for directing pressurized air outwardly through said outwardly directed channels when the spindle assembly is stopped at said predetermined position such that air is drawn in through said hollow axle to facilitate the threading of a yarn end therethrough.
 2. The apparatus as defined in claim 1 wherein said brake means includes a brake shoe and first pneumatic means for selectively pressing said brake shoe against said whorl.
 3. The apparatus as defined in claim 2 wherein said control means comprises means for directing pressurized air between said brake shoe and said whorl to form an air cushion therebetween, and a radially directed aperture in said whorl for carrying away a substantial portion of said pressurized air to thereby dissipate said air cushion when said spindle assembly is at said predetermined position.
 4. The apparatus as defined in claim 3 wherein said means for directing pressurized air outwardly through said outwardly directed opening comprises a passageway extending between said aperture and said outwardly directed opening whereby the pressurized air entering said aperture when said spindle assembly is at said predetermined position is directed into and exits outwardly through said outwardly directed opening.
 5. The apparatus as defined in claim 4 wherein said means for directing pressurized air between said brake shoe and said whorl includes a raDially directed outlet opening extending through said brake shoe and adapted to extend co-axially with said aperture in said whorl when said spindle assembly is at said predetermined position, and second pneumatic means for directing pressurized air outwardly through said outlet opening.
 6. The apparatus as defined in claim 5 wherein said first pneumatic means for selectively pressing said brake shoe against said whorl includes thread detector means for automatically actuating said first pneumatic means upon the breakage of the yarn being processed.
 7. The apparatus as defined in claim 6 wherein said second pneumatic means for directing pressurized air outwardly through said outlet opening includes valve means for actuating said second pneumatic means after actuation of said first pneumatic means.
 8. A textile yarn processing apparatus such as a twister, spinning frame or the like and having a plurality of rotatable spindle assemblies for processing of yarn and forming packages of processed yarn, each of said spindle assemblies including a hollow axle and an outwardly directed channel communicating with said hollow axle and through which the yarn is adapted to travel, a whorl portion, a tangential drive belt adapted to operatively engage said whorl portion to rotate said spindle assembly, and a tension roller for biasing said drive belt against said whorl portion, the improvement therewith of means for stopping rotation of said spindle assembly in a predetermined position and comprising a. brake means including a brake shoe adapted to frictionally engage said whorl for initially stopping rotation of said spindle and including means for concurrently withdrawing said tension roller from said drive belt such that said drive belt only loosely engages said whorl portion, and b. pneumatic control means for at least partially releasing said braking means to permit rotation of said spindle assembly only until said predetermined position is reached and including means for forming an air cushion between said brake shoe and said whorl such that the loose engagement of said drive belt with said whorl portion causes rotation of said spindle assembly and means for dissipating said air cushion when said predetermined position is reached, and means for directing air outwardly through said outwardly directed opening when the spindle assembly reaches said predetermined position such that air is drawn through said hollow axle to facilitate the treading of a yarn end therethrough.
 9. A textile yarn processing apparatus such as a twister, spinning frame or the like and having provision for stopping the rotation of each spindle assembly in a predetermined position and for facilitating the threading of a yarn end through the assembly when the same is stopped at said predetermined position, said apparatus comprising a plurality of rotatable spindle assemblies for processing of yarn, each of said spindle assemblies comprising a hollow axle and an outwardly directed channel communicating with said hollow axle and through which the yarn is adapted to travel, a whorl portion including a braking surface and a radially directed aperture communicating with said braking surface, and an air passage extending from said radially directed aperture in said whorl portion to said outwardly directed channel whereby air entering said radially directed aperture under pressure passes outwardly through said outwardly directed channel, a drive belt adapted to tangentially engage said whorl portion of each spindle assembly to rotate the same, a tension roller operatively associated with each spindle assembly for biasing said drive belt against said whorl portion, brake means for initially stopping rotation of a selected one of said spindle assemblies and comprising a brake shoe adapted to overlie said braking surface of said whorl portion, and pneumatically actuated piston means for selectively radially pressing said brake shoe into frictional engagement with said brakIng surface, and control means including an air outlet opening extending through said brake shoe for selectively directing pressurized air between said brake shoe and said braking surface to form an air cushion therebetween, whereby the selected spindle assembly may be initially stopped in a predetermined position by actuating said piston means to press the brake shoe into frictional engagement with said braking surface, and then brought to its predetermined position by actuating said control means to form an air cushion between said brake shoe and said braking surface and thereby at least partially release the frictional engagement therebetween such that the spindle assembly rotates until the radially directed aperture underlies the brake shoe, at which point the pressurized air forming the air cushion enters the radially directed aperture and passes outwardly through the outwardly directed channel to thereby dissipate the air cushion and thus again stop rotation of the spindle assembly and while drawing air through said hollow axle to facilitate the threading of a yarn end therethrough.
 10. The apparatus as defined in claim 9 wherein each of said tension rollers is pivotally mounted adjacent its associated spindle assembly and said brake means includes means for pivoting said tension roller away from said drive belt such that said drive belt only loosely engages said whorl portion when said brake shoe is pressed into frictional engagement with said braking surface.
 11. The apparatus as defined in claim 10 wherein said apparatus includes a separate one of said brake means and said control means fixedly mounted at each spindle assembly.
 12. The apparatus as defined in claim 10 wherein said brake means and said control means are mounted on a carriage, and said apparatus includes means for mounting said carriage to said apparatus to permit the carriage to be translated along the apparatus and be positioned in an operative position adjacent a selected one of said spindle assemblies.
 13. The apparatus as defined in claim 12 wherein said apparatus further comprises means operatively associated with each spindle assembly for initially stopping the rotation of the same and which acts independently of said brake means and said control means such that the rotation of the spindle assembly may be stopped while awating the arrival of said carriage.
 14. The apparatus as defined in claim 13 wherein said means for initially stopping the rotation of the spindle assembly includes a radially translatable brake slide, and thread detector means for translating said brake slide aginst said whorl immediately upon the breakage of the yarn being processed.
 15. The apparatus as defined in claim 14 wherein said carriage includes means for continuously translating the carriage along the apparatus, and engagement means for automatically stopping the translation upon the carriage reaching a spindle assembly which requires servicing.
 16. The apparatus as defined in claim 15 wherein said engagement means further includes means for withdrawing said brake slide from said whorl and actuating said brake means concurrently upon the stopping of the carriage at the spindle assembly.
 17. The apparatus as defined in claim 16 wherein said control means includes delay valve means for automatically actuating said control means after said engagement means has been actuated.
 18. The apparatus as defined in claim 17 wherein said apparatus further comprises manually operable switch lever means for withdrawing said brake shoe from said whorl and engaging said carriage translating means upon completion of the servicing at the spindle assembly. 